Apparatus and Methods for Plugging a Tubular

ABSTRACT

Segmented plug devices for insertion within a tubular to provide for flow restriction and isolation of selected sections within the tubular. Systems for plugging a tubular using an expandable segmented plug to form a ring that engages with an element to obstruct flow along the tubing. Tools for deploying and setting segmented plug devices within a tubular.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent Application No. 62/627,049, filed on Feb. 6, 2018, titled “Apparatus and Methods for Plugging a Tubular.” The entire disclosure of Application No. 62/627,049 is hereby incorporated herein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

Not applicable.

TECHNICAL FIELD OF THE INVENTION

This disclosure relates generally to techniques for plugging tubulars and, more particularly to improved plug devices to restrict fluid flow within selected sections in a tubular.

BACKGROUND

In the oilfield industry, the completion of subsurface wells to produce hydrocarbons entails the insertion of casing tubulars into a wellbore traversing the subsurface formations. Specialized tools are then inserted into the casing to perforate the walls of the tubular at desired subsurface locations in order to allow the hydrocarbons in the surrounding formation to flow into the casing for collection at the surface. Once the casing is perforated, a well stimulation technique known as hydraulic fracturing is applied to create cracks in the rock formations surrounding the wellbore to create fissures or fractures through which natural gas, petroleum, and other fluids can flow more freely. In this process, a fluid is injected into the casing at high-pressure to penetrate the formation via the perforations in the casing.

Some reservoirs, such as unconventional shale reservoirs, require that the wellbore be drilled horizontally and completed using multi-stage hydraulic fracturing. The hydraulic fracturing of a particular stage along the casing requires the casing to be perforated and the remainder of the horizontal well to be plugged or sealed. In this way, the hydraulic fracture will be created at the location of the perforations. In such operations, a “plug” is set in the casing prior to perforating to seal off the casing section to receive the high-pressure fluid.

A number of techniques have been developed to plug or seal casing tubulars. Conventional plug devices are deployed in the casing using a setting tool to install the plug. Such plug devices are typically annular in shape and have a hole or opening in the center to allow for fluid passage. A common technique for closing off the hole in the plug device entails the use of a ball. Once the plug is set, the plug setting tool is removed from the well and a spherical ball is inserted into the casing at the surface. The start of the hydraulic fracturing operation begins with pumping liquid into the casing at a relatively low rate. This flow pushes the ball down the casing until it reaches the plug. A ball with a larger diameter than the plug hole is used to ensure that the ball does not pass through the plug. The ball lodges against the opening in the plug and the combination of the ball and plug block flow of the fluid from going further. Continued pumping of the fluid from the surface results in increased pressure within the casing. As the pumping rate is increased, the pressure rises more rapidly until the reservoir fractures. Once the fracture is initiated, pumping continues until the desired volume of fluid has been pumped through the casing perforations and into the surrounding rock formation. Subsequent stages along the casing are created in the same way, until all the stages have been fractured.

Once all the stages have been fractured, the series of plugs are removed so that the well can be produced via the perforations from all the stages. This can be done in several ways. In one method, the balls are produced back to the surface by the fluid entering the perforated casing from the formation. This requires that the balls increase in size from one plug to the next in the uphole direction. In another method, the balls may be constructed of a material that dissolves over time. Once the balls are retrieved or dissolve, if the flow along the casing is excessively impeded by the plugs, the plugs may need to be removed. This typically requires that the plugs be drilled out or that the plugs themselves be dissolvable. A shortcoming of plugs that are drilled out is that they leave debris in the well. This debris can create problems with subsequent operations in the well, or at the surface, should it be produced. The volume of debris is determined by the volume of the plug. Conventional plugs tend to be long and thick structures, producing a significant volume of debris when they are drilled out.

Thus, a need remains for improved techniques for plugging tubulars and isolating sections within tubulars to restrict the passage and flow of fluids therethrough.

SUMMARY

According to an aspect of the invention, a plug apparatus includes a plurality of segments configured to interact with one another to form a ring having a central opening; wherein the plurality of segments are configured for disposal within a tubular; and wherein the plurality of segments are each configured to move in a radial direction from the center of the ring when a force is applied to at least one of the plurality of segments.

According to another aspect of the invention, a plug system includes a plurality of segments configured to interact with one another to form a ring having a central opening; wherein the plurality of segments are configured for disposal within a tubular; wherein the plurality of segments are each configured to move in a radial direction from the center of the ring when a force is applied to at least one of the plurality of segments; and an element configured for disposal within the tubular to engage with and obstruct the central opening of the ring.

According to another aspect of the invention, a method for plugging a tubular includes disposing a plurality of segments within a tubular, wherein the segments are configured to interact with one another to form a ring having a central opening; moving each segment of the plurality of segments in a radial direction from the center of the ring to contact an inner surface of the tubular; and disposing an element within the tubular to engage with and obstruct the central opening of the ring.

BRIEF DESCRIPTION OF THE DRAWINGS

The following figures form part of the present specification and are included to further demonstrate certain aspects of the present claimed subject matter, and should not be used to limit or define the present claimed subject matter. The present claimed subject matter may be better understood by reference to one or more of these drawings in combination with the description of embodiments presented herein. Consequently, a more complete understanding of the present embodiments and further features and advantages thereof may be acquired by referring to the following description taken in conjunction with the accompanying drawings, in which like reference numerals may identify like elements, wherein:

FIG. 1, in accordance with some embodiments of the present disclosure, depicts a cutaway side view of a series of segments configured in a ring structure to form a plug for insertion in a tubular;

FIG. 2A, in accordance with some embodiments of the present disclosure, depicts a perspective of a plug segment;

FIG. 2B, in accordance with some embodiments of the present disclosure, depicts another perspective of the plug segment of FIG. 2A;

FIG. 3A, in accordance with some embodiments of the present disclosure, depicts a perspective of another plug segment;

FIG. 3B, in accordance with some embodiments of the present disclosure, depicts another perspective of the plug segment of FIG. 3A;

FIG. 4, in accordance with some embodiments of the present disclosure, depicts a perspective of another plug segment;

FIG. 5, in accordance with some embodiments of the present disclosure, depicts a perspective of another plug segment;

FIG. 6, in accordance with some embodiments of the present disclosure, depicts a setting tool for placing a segmented plug in a tubular;

FIG. 7, in accordance with some embodiments of the present disclosure, depicts a cutaway view of the setting tool of FIG. 6;

FIG. 8, in accordance with some embodiments of the present disclosure, depicts a detailed view of the setting tool of FIG. 6;

FIG. 9, in accordance with some embodiments of the present disclosure, depicts a cutaway side view of a segmented plug expanded to form a ring anchored within a tubular;

FIG. 10, in accordance with some embodiments of the present disclosure, depicts an overhead view of an expanded plug anchored within a tubular;

FIG. 11, in accordance with some embodiments of the present disclosure, depicts a cutaway side view of a plug system;

FIG. 12, in accordance with some embodiments of the present disclosure, depicts a cutaway side view of another plug system;

FIG. 13, in accordance with some embodiments of the present disclosure, depicts another embodiment of a plug assembly; and

FIG. 14, in accordance with some embodiments of the present disclosure, is a flow chart illustrating a process for plugging a tubular.

NOTATION AND NOMENCLATURE

Certain terms are used throughout the following description and claims to refer to particular components and configurations. As one skilled in the art will appreciate, the same component may be referred to by different names. This document does not intend to distinguish between components that differ in name but not function. In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . .” As used herein, the term “tubular” encompasses any type of tube structure (e.g., conduits, casing, pipes, risers, hoses, etc.) and thus is not to be limited to any specific structure.

DETAILED DESCRIPTION

The foregoing description of the figures is provided for the convenience of the reader. It should be understood, however, that the embodiments are not limited to the precise arrangements and configurations shown in the figures. Also, the figures are not necessarily drawn to scale, and certain features may be shown exaggerated in scale or in generalized or schematic form, in the interest of clarity and conciseness.

While various embodiments are described herein, it should be appreciated that the present invention encompasses many inventive concepts that may be embodied in a wide variety of contexts. The following detailed description of exemplary embodiments, read in conjunction with the accompanying drawings, is merely illustrative and is not to be taken as limiting the scope of the invention, as it would be impossible or impractical to include all of the possible embodiments and contexts of the invention in this disclosure. Upon reading this disclosure, many alternative embodiments of the present invention will be apparent to persons of ordinary skill in the art. The scope of the invention is defined by the appended claims and equivalents thereof.

Illustrative embodiments of the invention are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. In the development of any such actual embodiment, numerous implementation-specific decisions may need to be made to achieve the design-specific goals, which may vary from one implementation to another. It will be appreciated that such a development effort, while possibly complex and time-consuming, would nevertheless be a routine undertaking for persons of ordinary skill in the art having the benefit of this disclosure.

FIG. 1 depicts an embodiment of this disclosure. A plug 10 is comprised of several independent segments 12 collectively configured in a substantially toroidal or “doughnut” shape (FIG. 10). Each segment 12 is wedge-shaped to interact with the adjacent segments to form a ring with a central opening 62 (FIG. 10). FIG. 1 depicts the plug 10 prior to expansion, in a reduced diameter mode, for insertion within a tubular 16 (e.g. well casing). Embodiments of the plug 10 segments 12 may be fabricated from suitable metals using conventional techniques as known in the art (e.g., machining, casting, water-jet manufacturing, etc.).

In some embodiments, one or more of the segments 12 may be implemented with at least one protrusion 18 extending out from the segment surface forming the outer diameter of the ring. The protrusion(s) 18 may comprise a raised portion extending out from the segment 12 outer surface. Although FIG. 1 depicts a button-shaped protrusion 18, it will be appreciated that protrusions may be formed in any suitable shape or combination of shapes. Once expanded within the tubular 16 (described below), the outer surface of the plug 10 will make contact with the inner surface of the tubular. In operation, once the plug 10 is set in the desired position within the tubular 16, the plug should remain fixed in place. Thus, for applications in metallic tubulars 16, the protrusion(s) 18 may be formed from a metal with sufficient hardness (e.g. tungsten carbide, titanium, etc.) to grip or anchor to the inner surface of the tubular. For applications in non-metallic tubulars 16, the protrusion(s) 18 may be formed from any suitable material to provide the desired anchoring within the tubular. In yet other embodiments, the plug 10 may be configured without any protrusions 18. Some segment 12 embodiments may be formed as a unitary structure, with the protrusion(s) 18 formed as part of the segment body. Other segment 12 embodiments may have the protrusion(s) 18 added to the segment body (e.g., via brazing, press fitting, gluing etc.).

The segments 12 alternate between male and female segments. FIG. 2A depicts a male segment 12, viewed from the outer side and configured with a series of protrusions 18. FIG. 2B depicts the male segment 12, viewed from the inner side. The male segment 12 embodiment depicted in FIG. 2A is configured with an extension 20 on each side. Each extension 20 on the sides of the male segment 12 is configured to interact and engage with a slot 22 formed in the adjacent female segment 12 (FIG. 3A) when the segments are joined to form a toroid as depicted in FIG. 1. In some embodiments, the extensions 20 and slots 22 on the segments 12 form a type of dovetail joint that keeps the segments together during insertion within the tubular 16 and allows the segments to move with respect to one another during expansion of the plug 10. Male and female segment 12 embodiments may also be respectively configured with a series of projections 24 formed on either or both sides of the extensions 20 and slots 22. The projections 24 may be angled such that each segment 12 can move in one axial direction with respect to the adjacent segment, preventing the adjacent segments from returning to their original position once they are moved to expand the plug 10 (described below).

As depicted in FIG. 2A, segment 12 embodiments may also be implemented with a raised section 26 that extends out from the outer surface at one end of the segment. As depicted in FIG. 2B, some segment 12 embodiments may also be implemented with a taper 28 formed at one end on the inner side. FIG. 3A depicts an embodiment of a female segment 12, viewed from the outer side and configured with a series of protrusions 18, slots 22, projections 24, and a raised section 26. FIG. 3B depicts the female segment 12, viewed from the inner side and also configured with a taper 28 formed at one end. Although the segments 12 in FIGS. 2A, 2B, 3A and 3C are depicted with linear extensions 20 and slots 22 having sharp edges, embodiments of this disclosure are not to be limited to such a configuration. Other segment 12 embodiments may be implemented with angled or curved extensions and slots, or a series of extensions and slots.

FIG. 4 depicts another embodiment of a male segment 12, viewed from the outer side and configured with a series of protrusions comprising stepped ridges 30 on the outer surface. The segment 12 is also configured with extensions 20 on each side, and a series of projections 24 formed on either or both sides of the extensions. Embodiments may also be configured with a raised section 26 that extends out from the outer surface at one end of the segment 12. Some embodiments may also be configured with a taper 28 formed at one end on the inner side, as depicted in the embodiment of FIG. 2B. FIG. 5 depicts another embodiment of a female segment 12, viewed from the outer side and configured with a series of stepped ridges 30, slots 22, projections 24, a raised section 26, and a taper 28 formed at one end on the inner side.

Segment 12 embodiments may be implemented with one or multiple ridges 30 formed on the outer surface of the segment. The ridges 30 may be implemented as a series of peaks and valleys formed on the segment 12 via conventional manufacturing processes. For applications where additional hardness is desired, the ridges 30 may be carburized via conventional techniques as known in the art. Some embodiments may be configured with a combination of ridges 30 and protrusions 18 implemented on the outer surface of the segment 12 (not shown). Yet other plug 10 embodiments may be configured with some segments 12 on the ring implemented with protrusions 18 and other segments on the ring implemented with ridges 30 (not shown). Some plug 10 embodiments may be formed with the ridge 30 protrusions having sharp edges, forming a series of teeth-like extensions that allow the segments 12 to more securely anchor against the inner surface of a tubular when the plug assembly is expanded (FIG. 9).

Turning to FIG. 6, an embodiment of a plug 10 setting tool 34 of this disclosure is depicted. The setting tool 34 may be used to deploy and set the plug 10 embodiments within tubulars 16. Embodiments of the setting tool 34 comprise an elongated cylindrical housing 36 and an internal telescoping mechanism (described below). For oilfield applications, the setting tool 34 may be formed of suitable metals and in various external diameters for use in different size tubulars (e.g. within well casing) as known in the art. In oilfield applications, the setting tool 34 may be deployed within the tubular 16 using a conventional wireline 38 (or cable tubing) as known in the art. The un-expanded plug 10 is positioned near the lower end of the setting tool 34. A gauge ring 40 is mounted at the lower end of the tool 34. FIG. 7 depicts a cutaway view of the setting tool 34.

As depicted in FIG. 7, the setting tool 34 comprises a first sleeve 42 coaxially disposed on the housing 36. The first sleeve 42 is rigidly mounted to the housing 36, terminating with a plurality of first sleeve legs 44 extending out from the housing's open end. The first sleeve legs 44 are narrow and extend parallel to one another along the longitudinal axis of the tool 34. The legs 44 extend out circumferentially, in a cage-like pattern with open gaps between adjacent legs. An individual plug 10 segment 12 is mounted at the end of each first sleeve leg 44.

The setting tool 34 is configured with a telescoping mechanism comprising an inner sleeve 46 coaxially disposed within the housing 36. The inner sleeve 46 is of a smaller diameter than the first sleeve 42, allowing the inner sleeve to reside and slide within the first sleeve. The inner sleeve 46 terminates at the lower end of the setting tool 34 with a plurality of inner sleeve legs 48 extending out from the open end in the housing 36. The inner sleeve legs 48 are narrow and extend parallel to one another along the longitudinal axis of the tool 34. The legs 48 extend out circumferentially, in a cage-like pattern with open gaps between adjacent legs. The end of each inner sleeve leg 48 is affixed to the gauge ring 40. Each inner sleeve leg 48 also holds an individual plug 10 segment 12 between the housing 36 open end and the gauge ring 40. FIG. 8 depicts the setting tool 34 plug 10 attachment configuration in greater detail.

FIG. 8 depicts the lower end of a setting tool 34 embodiment disposed within a tubular 16 (e.g. well casing). The first sleeve legs 44 are shorter than the inner sleeve legs 48. A plug 10 segment 12 is mounted at the end of each first sleeve leg 44, held via a shear pin 50 disposed in an orifice on the inner side of the segment. Each inner sleeve leg 48 also holds a plug 10 segment 12, also held via a shear pin 50 disposed in an orifice on the inner side of the segment. Since the plug 10 is mounted on the setting tool 34 in an un-expanded mode (FIG. 1), the segments 12 are mounted on the first and inner sleeve legs 44, 48 axially offset from one another. Thus, each first sleeve leg 44 holds an ‘upper’ segment 12 and each inner sleeve leg 48 holds a ‘lower’ segment 12. The upper and lower segments 12 are mounted on the first and inner sleeve legs 44, 48 in a partially engaged mode (i.e., the extensions 20 and slots 22 in adjacent segments are partially engaged with one another).

The gauge ring 40 is a donut-shaped member with a central opening 52. As depicted in FIG. 8, the central opening 52 is formed with a stepped inner diameter. The inner diameter of the central opening 52 matches the outer diameter of the inner sleeve legs 48 for a portion of the gauge ring 40 body. The inner diameter of the central opening 52 is slightly smaller for the remaining portion of the gauge ring 40 body. In this manner, a circumferential ledge 54 is provided within the gauge ring 40 central opening 52. All ends of the inner sleeve legs 48 are disposed in the larger diameter end of the gauge ring 40 central opening 52. The terminal ends of the inner sleeve legs 48 abut the circumferential ledge 54. The gauge ring 40 is secured to one or more inner sleeve legs 48 via shear pins 56 disposed in orifices formed in the gauge ring body. In operation, the gauge ring 40 protects the plug 10 segments 12 from being damaged as the setting tool 34 is deployed into the tubular 16.

Once the setting tool 34 (fitted with the plug 10) is deployed within the tubular 16 to the desired location, an activation mechanism 60 (FIG. 6) is actuated to move the inner sleeve 46 into the housing 36. As the inner sleeve 46 slides into the housing 36, the inner sleeve legs 48 move relative to the stationary first sleeve legs 44, thereby applying an axial force on the segments 12 such that the lower and upper segments interact to slide into each other. This causes the plug 10 ring to form, as it compresses axially and expands radially from the center. The first sleeve legs 44 and inner sleeve legs 48 also expand and bow out radially as the segments 12 slide into each other. The force required to move the legs 44, 48 relative to each other is low, until such time that the plug 10 ring expands enough to engage with the tubular 16. Once this happens, the force rises, causing the plug 10 ring segments 12 to anchor against the tubular 16 inner surface to set the ring in place. A continued rise in the force applied to the inner sleeve 46, by the activation mechanism 60, eventually causes the shear pins 50 that secure the segments 12 to the legs 44, 48 to break (e.g. resulting from 50,000 lbs. of axial force). When this happens, the plug 10 ring is now expanded and disconnected from the legs 44, 48. At this point the legs 44, 48 are no longer in contact with the segments 12, and the setting tool 34 is now disconnected from the plug 10 and can be retrieved from the tubular 16. The plug 10 is set.

Since the gauge ring 40 is also pinned to the inner sleeve legs 48, once the legs disengage from the lower segments 12 the legs pass through the central plug 10 opening as the setting tool 34 is retrieved from the tubular 16, until the gauge ring abuts the anchored plug and the gauge ring shear pin(s) 56 breaks. When this happens the gauge ring 40 becomes a loose body in the tubular 16.

Embodiments of the plug 10 can be made for applications in tubulars 16 of different inner diameters. Similarly, embodiments of the setting tool 34 can also be implemented with appropriately sized housing 36 diameters to accommodate different diameter tubulars 16. It will be appreciated by those skilled in the art that conventional shear pin 50, 56 devices and activation mechanisms 60 (e.g., hydraulic, pneumatic, electric servo, etc.) may be used to implement the setting tool 34. It will also be appreciated by those skilled in the art that conventional downhole tool electronics and hardware may be used to implement setting tool 34 embodiments of this disclosure. Actuation of the activation mechanism 60 may be achieved via electric signal communication (e.g. along a wireline 38 or cabled tubing). In some embodiments, electronics in the insertion tool 34 may include a processor programmed with instructions to automatically actuate the activation mechanism 60 to set the plug 10 when the tool reaches a specified depth or position within the tubular 16.

FIG. 9 depicts a side view of a plug 10 embodiment with ridge 30 protrusions after it has been set in a tubular 16. FIG. 10 depicts an overhead view of a plug 10 embodiment after it has been set in a tubular 16. The central opening 62 of the plug 10 allows for unobstructed passage and flow of liquids and gases along the tubular 16. With segment 12 embodiments formed with a taper 28, once the plug 10 is expanded, an angled circumferential landing 64 is formed at the upper plug surface. It will be appreciated that although the plug 10 in FIG. 10 is depicted with sixteen segments 12, other embodiments may be implemented with more or less individual segments forming the ring.

In completion operations, after the plug 10 is set at the desired location within the tubular 16 and the setting tool 34 is tripped out of the tubular, a plugging element is inserted into the tubular from the surface. A ball or dart are often used to plug or restrict fluid flow along the wellbore. FIG. 11 depicts a ball 66 sitting and engaged atop the plug 10. As well known in the art, the ball 66 may be conveyed down the tubular 16 with the fluid being pumped in from the surface. The diameter of the ball 66 is greater than the diameter of the plug's 10 central opening 62 after the plug has been expanded. As the ball 66 is conveyed along the tubular 16, it eventually engages with and sits atop the plug 10 to obstruct the plug's central opening 62. The circumferential landing 64 cups the ball 66 atop the ring 10, forming a better seal. As depicted in FIG. 11, the combination of the plug 10 and ball 66 plugs the tubular 16, effectively restricting the flow of fluids past the plug. With segment 12 embodiments configured with raised sections 26, once the plug 10 is expanded, the raised sections form an annular lip 68 that presses against the inner surface of the tubular 16 to form a circumferential seal around the plug.

FIG. 12 depicts a dart 70 sitting atop and engaged in the plug 10. As well known in the art, a dart 70 may be conveyed down the tubular 16 with the fluid being pumped in from the surface. Embodiments of the dart 70 may be implemented with a cup seal 72 and a compression seal 74 to provide additional sealing. Once the plugging element (e.g. ball or dart) is in place, the fluid being pumped into the tubular 16 seats and maintains the element within the plug 10 ring opening, preventing flow past the plug. As the fluid pressure is increased, hydraulic fracturing of the rock formation is achieved at the tubular section isolated by the plug 10 (not shown).

As previously discussed, embodiments of the plug 10 may be made of metal. In addition to metallic embodiments, some plug 10 embodiments may also be produced with segments 12 formed using composite materials or materials that dissolve when exposed to certain fluids as known in the art. It is well known that magnesium-based components may be used in oilfield applications where the components are exposed to high pressure and high temperature to perform their functions for a projected period of time before they start disintegrating in the wellbore. Conventional balls 66 and darts 70 used in oilfield operations may be used to implement embodiments of this disclosure. Some embodiments may also be implemented using conventional balls 66 and darts 70 formed from dissolvable materials. For example, dissolvable frac balls available from DISSOLVALLOY™ (www.dissolvalloy.com) can be used to implement the disclosed embodiments. Similarly, embodiments of the gauge ring 40 may also be formed from dissolvable materials. Dissolvable plug 10, gauge ring 40, ball 66, and dart 70 embodiments disappear over time, so they do not become an obstruction or create debris, eliminating the need to retrieve or drill out these components from the tubular 16. Other plug 10 embodiments may be formed with a combination of metallic and non-metallic segments 12 as suitable for the particular application. It will be appreciated by those skilled in the art that embodiments of this disclosure may be implemented using conventional materials and combinations of materials as desired for the particular application.

FIG. 13 depicts another plug 10 embodiment. In this embodiment, a ring is formed from four independent segments 12. The plug 10 is depicted with the segments 12 in partial engagement. The segments 12 respectively comprise the extensions 20, slots 22, and projections 24 on the sides. The segments 12 are also implemented with a taper 28 formed at one end on the inner side. Some embodiments are configured with a series of protrusions 76 comprising ridges on opposite ends of the segment 12 outer surface. The protrusions 76 may extend across the entire width of the segment 12 to form bands as depicted in FIG. 13, or they may only extend across a portion of the segment 12. In some embodiments, the ridges 76 may be beveled or differ in the extent they individually protrude from the segment 12 surface, forming a series of stepped bands. As depicted in FIG. 13, some plug 10 embodiments may be formed with some segments comprising the protrusions 76 on each end of the outer surface and other segments having the protrusions 76 formed only on one end. This embodiment may also be deployed with a tubular using the disclosed setting tool 34 in the manner described herein. Those skilled in the art will appreciate that the setting tool 34 may be configured with the appropriate number of sleeve legs 44 to correspond with the respective plug 10 embodiment segments 12.

In accordance with some embodiments, FIG. 14 is a flow chart illustrating a process 100 for plugging a tubular. At step 110, a plurality of segments are disposed within a tubular, wherein the segments are configured to interact with one another to form a ring having a central opening. At step 120, each segment of the plurality of segments is moved in a radial direction from the center of the ring to contact an inner surface of the tubular. At step 130, an element is disposed within the tubular to engage with and obstruct the central opening of the ring. This process may be implemented using the techniques and embodiments disclosed herein.

It will be appreciated that plug 10 embodiments can be implemented in different sizes and diameters depending on the desired application. An advantage of the disclosed plug 10 embodiments for use in oilfield applications is the short axial length of the device (e.g., embodiments can be less than 6 inches in height). Once set in a tubular, the internal plug 10 diameter is large. For example, in 5½ inch casing tubing having an internal diameter of 4.892 inches, the internal diameter of a plug 10 embodiment can be 3.5 inches or larger.

In light of the principles and example embodiments described and depicted herein, it will be recognized that the example embodiments can be modified in arrangement and detail without departing from such principles. Also, the foregoing discussion has focused on particular embodiments, but other configurations are also contemplated. Even though expressions such as “in one embodiment,” “in another embodiment,” or the like are used herein, these phrases are meant to generally reference embodiment possibilities, and are not intended to limit the invention to particular embodiment configurations. As used herein, these terms may reference the same or different embodiments that are combinable into other embodiments. As a rule, any embodiment referenced herein is freely combinable with any one or more of the other embodiments referenced herein, and any number of features of different embodiments are combinable with one another, unless indicated otherwise.

In view of the wide variety of useful permutations that may be readily derived from the example embodiments described herein, this detailed description is intended to be illustrative only, and should not be taken as limiting the scope of the invention. What is claimed as the invention, therefore, are all implementations that come within the scope of the following claims, and all equivalents to such implementations. 

What is claimed is:
 1. A plug apparatus, comprising: a plurality of segments configured to interact with one another to form a ring having a central opening; wherein the plurality of segments are configured for disposal within a tubular; and wherein the plurality of segments are each configured to move in a radial direction from the center of the ring when a force is applied to at least one of the plurality of segments.
 2. The plug apparatus of claim 1, wherein the plurality of segments are configured to move in a radial direction to expand from the center of the ring when an axial force is applied to at least one of the plurality of segments.
 3. The plug apparatus of claim 1, wherein the plurality of segments are configured to move in an axial direction relative to one another when an axial force is applied to at least one of the plurality of segments.
 4. The plug apparatus of claim 1, wherein the plurality of segments are formed from a material comprising: (a) metal; (b) composite; or (c) ceramic.
 5. The plug apparatus of claim 1, wherein the plurality of segments are formed from a material comprising a dissolvable material.
 6. The plug apparatus of claim 1, wherein at least one of the plurality of segments comprises at least one protrusion configured to contact an inner surface of the tubular when the at least one segment moves in a radial direction from the center of the ring.
 7. The plug apparatus of claim 1, wherein the central opening is configured to receive an element to obstruct the opening.
 8. The plug apparatus of claim 1, wherein the ring is formed from four segments.
 9. The plug apparatus of claim 1, wherein the ring is formed from more than four segments.
 10. A plug system, comprising: a plurality of segments configured to interact with one another to form a ring having a central opening; wherein the plurality of segments are configured for disposal within a tubular; wherein the plurality of segments are each configured to move in a radial direction from the center of the ring when a force is applied to at least one of the plurality of segments; and an element configured for disposal within the tubular to engage with and obstruct the central opening of the ring.
 11. The plug system of claim 10, wherein the plurality of segments are disposed on a tool configured for disposal within the tubular.
 12. The plug system of claim 10, wherein the plurality of segments are formed from a material comprising: (a) metal; (b) composite; or (c) ceramic.
 13. The plug system of claim 10, wherein the plurality of segments are formed from a material comprising a dissolvable material.
 14. The plug system of claim 10, wherein at least one of the plurality of segments comprises at least one protrusion configured to contact an inner surface of the tubular when the at least one segment moves in a radial direction from the center of the ring.
 15. The plug system of claim 10, wherein the ring is formed from four segments.
 16. The plug system of claim 10, wherein the ring is formed from more than four segments.
 17. A method for plugging a tubular, comprising: disposing a plurality of segments within a tubular, wherein the segments are configured to interact with one another to form a ring having a central opening; moving each segment of the plurality of segments in a radial direction from the center of the ring to contact an inner surface of the tubular; and disposing an element within the tubular to engage with and obstruct the central opening of the ring.
 18. The method of claim 17, wherein disposing the plurality of segments within the tubular comprises mounting the segments on a tool configured for disposal within the tubular.
 19. The method of claim 17, wherein the plurality of segments are formed from a material comprising a dissolvable material.
 20. The method of claim 17, wherein the ring is formed from four segments. 